Method for dividing bodies of lightweight concrete or similar material



Nov. 27,v 1962 METHOD FOR DIVIDING BODIES OF LIGHTWEIGHT CONCRETE OR SIMILAR MATERAL Filed March 4, 1957 ATTORNEYS P. AKE H. JAKoBssoN ETAL 3,065,514 A 3,065,514 METHOD FOR DIVIDING BODHES F LIGHT- VIIHT CONCRETE 0R SIMILAR MATE- Per Ake Henning .Iakobsson and Kari-Gustav Ohm,

'Kumia, Sweden, assignors to International Ytong-Stabalite Company Limited, London, England, a corporation of Great Britain Filed Mar. 4, 1957, Ser. No. 643,557 4 Claims. (Ci. 25-155) This invention relates to a method for dividing bodies of lightweight concrete or similar material cast on a band.

In the planning of factories for production of lightweight concrete the question of transporting the bodies has always played a conspicuous part. In the usual method, the raw compound, which will become light- Weight concrete, is cast into large moulds in which it becomes porous. During this process the compound will set to such an extent that it has a self-bearing consistency. In this state the mould content is divided into smaller units.

The moulds, in which the compound is cast, are placed on trucks running on rails, and because of the fact that the casting-sections are generally located at a fixed place the moulds have to be removed from the casting-place after casting to drying and dividing tracks. This removal of the moulds has to be done carefully because the compound can be damaged very easily in this stage. For this reason it is important that the transport arrangements for the removal of the moulds containing the new-cast compound allow a soft acceleration and retardation and traversing without jerks. This problem, however, has not always been solved in a desirable way.

In order to eliminate diiculties arising in connection with transporting of relatively heavy moulds, the thought occurred that it might be possible to cast the lightweight concrete directly on a moving surface or belt. This method, however, gave rise to other problems, such as how to divide the mass into smaller units while on the belt.

The present invention provides a solution to this problem. In the method according to the invention, the forming mass is transferred from one moving belt to a second moving belt, and the mass is divided into smaller units or blocks while being so transferred, the dividing means being disposed between the two belts. A principal feature of the invention is that the second belt is moving at a slower rate of speed than the first belt so that the mass is subjected to compression while being transferred from one to the other. This eliminates breakage or distortion of the forming mass due to a lack of support while the mass is moving through the dividing means.

A device for performing the method according to the invention is described below with reference to FIG. I which in a perspective sketch shows a dividing apparatus.

The dividing apparatus shown in FIG. I consists of two main parts, namelya delivering part and a receiving part 11. Between those parts a Wire frame 12 is attached. In this wire frame horizontal as well as vertical dividing wires are stretched.

The delivering part 10 consists of a travelling band or belt 13, which is stretched between two rolls 14 and 15. In the space which is formed by the band, a supporting plate 16 is placed. The supporting plate 16 is supported by a strand 17 in which the rolls 15 and 14 are placed.

The receiving part 11 consists of a table 18 which is provided with a roll 19 at one end. Partially drawn up on the table and lying above the roll 19 a plate 20 is shown which is constructed of a flexible but nevertheless 3,065,514 Patented Nov. 27, 1962 stiff material. At one end of ther plate a drawing device 21 is fastened.

At the delivering part 10 a device for dividing the bodies in the vertical direction is mounted. It consists of a stand 22 and a frame 23. In the open end on frame 23 a dividing wire 24 is stretched. The frame 23 is movable in the vertical direction.

A mass block 25 is shown in its position during longi tudinaland cross-dividing.

The device operates as follows:

At the beginning of the dividing the mass block 25 is situated on the delivering part 10 and the plate 20 is placed with its A-marked end at point B on the table 18. Then the band 13 is started up whereby the mass block 25 is led forward to and through the dividing frame 12 which is provided with stretched wires. Simultaneously when the travelling band 13 begins to move the Plate 19 is started. The speed of plate 19, however, is put somewhat lower than that of the band, therefore the mass block is compressed somewhat when passing the space which is formed between the main parts of the dividing apparatus and in which the dividing frame is placed. The risk that the mass block might break during the dividing is thereby eliminated.

When the massblock has been completely divided it lies on the plate 20 on the table 18. From there it can be removed to a hardening truck or over further rollers towards the autoclaves for steamhardening with the plate serving as a bottom.

When dividing a cast piece in its longitudinal direction a bottom layer of a few centimeters thickness is always removed, because otherwise the lowest body would show a surface of completely flattened pores impregnated with oil. from the mould. Up to now this layer has also gone into the autoclave during the hardening of the block. This is, however, unnecessary and there are certain advantages to removing the layer before hardening. This can be done easily during the dividing which is described above, by simply attaching a knife behind the dividing frame, whch breaks the thin cut olic layer so that it falls down into the space between the two main parts of the dividing apparatus. However, the knife has to be placed in such a way that it does not damage the cleancut bottom surface.

In order to make it possible for the cleancut body to be moved to the receiving part without breaking, the receiving part has to be as much higher than the delivering part as the cut olf layer is thick. Therefore the receiving part must be arranged in such a way that it can be raised -and lowered for a considerable distance.

Certain types of lightweight concrete are inclined to adhere to the supporting plate during the steam-hardening. This disadvantage is eliminated very easily if a thin paper, for instance ordinary wrapping-paper, is put on the supporting plate. Unexpected-ly, it has been shown that the lightweight concrete does not adhere to this paper, and it is very easily removed after hardening. The paper is not wasted during the hardening, and it can be used several times.

In the performance described only longitudinal dividing of the mould content has been described. It may, however, be necessary to divide the mass block in a cut -at right angles to its longitudinal direction. This can be done very easily by applying a dividing wire in connection with the dividing frame, which divides the mass block in desirable longitudinal units by means of vertical cuts. By this method, however, the mass block has to be stopped every time a vertical cut is to be performed by the wire. and it has been shown that marks are then obtained in the block owing to changes of the stress in the wires dividing the mass block in the longitudinal direction. The simplest way to avoid this is to arrange that the wire which cuts the block in its lateral direction runs synchronously with the travelling band. Thus the wire cuts downward and at the same time forward in the direction of movement of the block instead of making'avertical cut. j

According to the device described, divided mass blocks on supporting plates have been obtained which can then be transferred to the steam-hardening. The device, however, can be used in such a way that it consists of only one travelling band, which forms the delivering as well as the receiving part. However, in order to have space for the dividing arrangement the band has to be bowed around stretching rolls. It is, of course, also possible to perform the dividing arrangement in such a way that the delivering and receiving part consist of two separat travelling bands.

What is claimed is:

1. A method for the production 'of lightweight concrete blocks and the like comprising the steps of disposing a mass of lightweight cementitious material of a suitable consistency for dividing on la laterally moving surface, transferring the mass to a second surface spaced apart from but adjacent to said iirst surface and moving in the same direction as said first surface at a lesser rate of speed so as to cause substantially non-deforming compression of the portion of said mass disposed between said two moving surfaces 4and dividing the mass longitudinally through said portion which is under corn- -pression and moving from said rst surface to said second surface.

2. A method according to claim 1 including the step of removing a thin layer from the bottom of the mass while the mass is being longitudinally divided, and said second surface is disposed at a higher level than said rst surface, the distance between the levels corresponding to the thickness of said layer removed from the bottom of said mass.

3. A method according to claim 1 including the step of dividing the mass transversely while said mass is under compression.

4. A method according to claim 1 including the step of feeding a thin sheet of paper between the bottom of said mass and said second surface. 

